Direct and indirect links between brain regions and cardiac function have been reported. We performed a systematic literature review to summarize current knowledge regarding the associations of heart rate variability (HRV) and brain region morphology, activity and connectivity involved in autonomic control at rest in healthy subjects. Both positive and negative correlations of cortical thickness and gray matter volumes of brain structures with HRV were observed. The strongest were found for a cluster located within the cingulate cortex. A decline in HRV, as well as cortical thickness with increasing age, especially in the orbitofrontal cortex were noted. When associations of region-specific brain activity with HRV were examined, HRV correlated most strongly with activity in the insula, cingulate cortex, frontal and prefrontal cortices, hippocampus, thalamus, striatum and amygdala. Furthermore, significant correlations, largely positive, between HRV and brain region connectivity (in the amygdala, cingulate cortex and prefrontal cortex) were observed. Notably, right-sided neural structures may be preferentially involved in heart rate and HRV control. However, the evidence for left hemispheric control of cardiac vagal function has also been reported. Our findings provide support for the premise that the brain and the heart are interconnected by both structural and functional networks and indicate complex multi-level interactions. Further studies of brain–heart associations promise to yield insights into their relationship to health and disease.

Purpose: The aims of this study were to 1) characterize and visualize the association between social connection and physical functioning using network analysis, with attention to different types of measures of these constructs, and 2) identify key indicators that link social connection and physical functioning. Methods: Data come from the 2014/2016 Health and Retirement Study (N = 7,270, mean age = 67.3). Network analysis was used to depict and explore the relationships between physical functioning and social connection. Both of these constructs were measured using a combination of “objective” (e.g., balance test, number of social connections) and “subjective” (e.g., self-evaluated activities of daily living (ADLs), perceived loneliness) indicators. The network was estimated using a regularized partial correlation network. Features of the network structure were characterized using 1) assortativity, 2) community detection, and 3) centrality indices (i.e., strength and betweenness). Betweenness centrality was used to identify the key nodes linking the two constructs. Results: The network structure is determined by constructs (i.e., social connection vs. physical functioning, assortativity = 0.87), instead of types of measures (i.e., objective vs. subjective, assortativity = 0.45). There are five communities identified from the network, three of which include both subjective and objective indicators. The incomplete balance tes t is the key bridging indicator that links social connection and physical functioning. Conclusion: The linkages between social connection and physical functioning are multifaceted. Balance impairment is the key bridge between these constructs for older adults.

Background: Our study examined how social disconnection, neighborhood contexts, and cognitive function trajectories are jointly and interactively associated among middle-aged and older Black adults. Methods: Data came from non-Hispanic Black participants aged 51 and older (n = 1791) from the Health and Retirement Study. Cognitive health was measured by a global cognitive function summary score. Social disconnectedness was measured by 3 types of social isolation (from extended family, adult children, and friends) and loneliness (UCLA 3-item Loneliness Scale). Neighborhood contextual factors included neighborhood social cohesion and physical disadvantage. Covariates included age, sex, education, marital status, and living arrangements. We used group-based trajectory modeling to test the study objectives. Results: We identified 4 global cognitive function trajectories: low and declining (14% of sample), moderate and declining (29%), moderate and stable (40%), and high and stable (17%). Multivariable models indicated that neighborhood physical disadvantage (RRR = 0.61, 95% CI [0.40, 0.92]) and social cohesion (RRR = 0.42, 95% CI [0.23, 0.77]) moderated the association between social isolation from extended family and global cognitive function trajectory membership. Conclusions: Our study is among the first to examine cognitive function trajectories with linkages to social disconnectedness and neighborhood contexts among middle-aged and older Black adults. Overall, the results suggest that neighborhood contexts condition how social isolation relates to cognitive trajectories. These findings underscore the importance of considering both social disconnectedness and neighborhood context in explaining heterogeneity in cognitive aging among middle-aged and older Black adults.